Wheel sensors are the main sources for the information needed for control in the known electronic control system for anti-lock control and traction slip control that are available on the market. The rotational behaviour of the individual wheels is measured by means of these sensors and the vehicle speed, or rather the reference speed of the vehicle, is derived from these measured values. By linking the signals it is moreover possible to detect to a more or less reliable extent whether the vehicle momentarily is driving straight onwards or is cornering, whether the friction coefficient is high or low, whether there is a danger of high yawing moments etc.
It is likewise known to use vehicle acceleration sensors. Other control systems additionally require braking pressure sensors.
For cost reasons, one aim is to get along with as few sensors as possible. On the other hand, there is a need for further information on the momentary behaviour of the vehicle in order to improve control, to exclude misinterpretation of the sensor information and to detect errors, or rather defects, in time.